1. Field of the invention
The present invention relates to a method for recording an image by using a photosensitive sheet which comprises a transparent substrate and microcapsules each of which encapsulates therein a photosensitive material having a viscosity which changes upon irradiation and a chromogenic material which develops color by reaction with a developer.
2. Description of Related Art
An image recording apparatus using this type of image recording method is disclosed in U.S. Pat. No. 4,985,727, issued on Jan. 15, 1991 and assigned to the same assignee as that of the present invention. That image recording apparatus uses the image recording method described below. U.S. Pat. No. 4,399,209 discloses in detail the structure of the microcapsules used in the recording method, that explanation being incorporated by reference.
A light source is first turned on to irradiate an original in the image recording apparatus. The light irradiated onto the original is reflected from the surface thereof. The light reflected from the surface of the original is transmitted through a focusing lens to a recording medium, the surface of which carries the microcapsules. The recording medium is thus exposed to the projected light consisting of a focused image of the original.
Each of the microcapsules carried on the surface of the recording medium encapsulates therein a photosensitive material, having a viscosity which changes upon irradiation, and a chromogenic material. Therefore, when the light reflected from the original is projected onto the recording medium to focus an image of the original thereon, a change is produced in the rigidity of the microcapsules in accordance with a change in the viscosity related to the amount of light irradiation. Each of the numerous microcapsules carried on the recording medium changes in its rigidity depending upon the amount of light irradiation to thereby form a chemical latent image corresponding to the image of the original on the recording medium. Subsequently, a photosensitive member is subjected to light exposure of the original image in the same manner as was the recording medium.
The photosensitive member is provided with a conductive substrate having a photoconductive layer containing photoconductive materials laminated thereon. When the light reflected from the original image is irradiated onto the photoconductive layer, charges in the layer change in accordance with the original image to form an electrostatic latent image on the photosensitive member corresponding to the original image. Next, the electrostatic a latent image formed on the photosensitive member is developed as latent image of a developer material. This developer latent image contains a developer material that reacts with the chromogenic material found in the microcapsules on the recording sheet to cause the chromogenic material to color. Thereafter, the recording medium is placed onto the photosensitive member so that the microcapsule latent image is superposed on the developer latent image for transferring the developer latent image onto the recording medium. Finally, the recording medium on which the developer latent image is transferred is superposed on an optional recording medium for developing the image under pressure. When pressure is applied to the superposed recording medium, having a developer latent image overlying the microcapsules, and the optional recording medium, the chromogenic material flows out of ruptured microcapsules and reacts with the developer to develop a color image that is recorded on the optional recording medium.
The above-mentioned image recording method makes it possible to record an image on a non-standard or optional recording medium such as a sheet or cloth which cannot be used in the conventional image recording method using the microcapsules.
However, in the aforesaid image recording method, it is difficult to perfectly superpose the developer latent image developed on the photosensitive member onto the chemical latent image formed on the recording medium, thereby resulting in frequent deviation between the developer image and the chemical image. Accordingly, there arises a problem that a part of the image portion which should be developed is not and a defective portion of the final image recorded on the optional recording medium results.